<?php

/*
 * This file is part of SwiftMailer. (c) 2004-2009 Chris Corbyn For the full copyright and license information, please view the LICENSE file that was distributed with this source code.
 */

/**
 * Handles Quoted Printable (QP) Encoding in Swift Mailer.
 * Possibly the most accurate RFC 2045 QP implementation found in PHP.
 * 
 * @package Swift
 * @subpackage Encoder
 * @author Chris Corbyn
 */
class Swift_Encoder_QpEncoder implements Swift_Encoder {
	/**
	 * The CharacterStream used for reading characters (as opposed to bytes).
	 * 
	 * @var Swift_CharacterStream
	 * @access protected
	 */
	protected $_charStream;
	
	/**
	 * A filter used if input should be canonicalized.
	 * 
	 * @var Swift_StreamFilter
	 * @access protected
	 */
	protected $_filter;
	
	/**
	 * Pre-computed QP for HUGE optmization.
	 * 
	 * @var string[]
	 * @access protected
	 */
	protected static $_qpMap = array (
			0 => '=00',
			1 => '=01',
			2 => '=02',
			3 => '=03',
			4 => '=04',
			5 => '=05',
			6 => '=06',
			7 => '=07',
			8 => '=08',
			9 => '=09',
			10 => '=0A',
			11 => '=0B',
			12 => '=0C',
			13 => '=0D',
			14 => '=0E',
			15 => '=0F',
			16 => '=10',
			17 => '=11',
			18 => '=12',
			19 => '=13',
			20 => '=14',
			21 => '=15',
			22 => '=16',
			23 => '=17',
			24 => '=18',
			25 => '=19',
			26 => '=1A',
			27 => '=1B',
			28 => '=1C',
			29 => '=1D',
			30 => '=1E',
			31 => '=1F',
			32 => '=20',
			33 => '=21',
			34 => '=22',
			35 => '=23',
			36 => '=24',
			37 => '=25',
			38 => '=26',
			39 => '=27',
			40 => '=28',
			41 => '=29',
			42 => '=2A',
			43 => '=2B',
			44 => '=2C',
			45 => '=2D',
			46 => '=2E',
			47 => '=2F',
			48 => '=30',
			49 => '=31',
			50 => '=32',
			51 => '=33',
			52 => '=34',
			53 => '=35',
			54 => '=36',
			55 => '=37',
			56 => '=38',
			57 => '=39',
			58 => '=3A',
			59 => '=3B',
			60 => '=3C',
			61 => '=3D',
			62 => '=3E',
			63 => '=3F',
			64 => '=40',
			65 => '=41',
			66 => '=42',
			67 => '=43',
			68 => '=44',
			69 => '=45',
			70 => '=46',
			71 => '=47',
			72 => '=48',
			73 => '=49',
			74 => '=4A',
			75 => '=4B',
			76 => '=4C',
			77 => '=4D',
			78 => '=4E',
			79 => '=4F',
			80 => '=50',
			81 => '=51',
			82 => '=52',
			83 => '=53',
			84 => '=54',
			85 => '=55',
			86 => '=56',
			87 => '=57',
			88 => '=58',
			89 => '=59',
			90 => '=5A',
			91 => '=5B',
			92 => '=5C',
			93 => '=5D',
			94 => '=5E',
			95 => '=5F',
			96 => '=60',
			97 => '=61',
			98 => '=62',
			99 => '=63',
			100 => '=64',
			101 => '=65',
			102 => '=66',
			103 => '=67',
			104 => '=68',
			105 => '=69',
			106 => '=6A',
			107 => '=6B',
			108 => '=6C',
			109 => '=6D',
			110 => '=6E',
			111 => '=6F',
			112 => '=70',
			113 => '=71',
			114 => '=72',
			115 => '=73',
			116 => '=74',
			117 => '=75',
			118 => '=76',
			119 => '=77',
			120 => '=78',
			121 => '=79',
			122 => '=7A',
			123 => '=7B',
			124 => '=7C',
			125 => '=7D',
			126 => '=7E',
			127 => '=7F',
			128 => '=80',
			129 => '=81',
			130 => '=82',
			131 => '=83',
			132 => '=84',
			133 => '=85',
			134 => '=86',
			135 => '=87',
			136 => '=88',
			137 => '=89',
			138 => '=8A',
			139 => '=8B',
			140 => '=8C',
			141 => '=8D',
			142 => '=8E',
			143 => '=8F',
			144 => '=90',
			145 => '=91',
			146 => '=92',
			147 => '=93',
			148 => '=94',
			149 => '=95',
			150 => '=96',
			151 => '=97',
			152 => '=98',
			153 => '=99',
			154 => '=9A',
			155 => '=9B',
			156 => '=9C',
			157 => '=9D',
			158 => '=9E',
			159 => '=9F',
			160 => '=A0',
			161 => '=A1',
			162 => '=A2',
			163 => '=A3',
			164 => '=A4',
			165 => '=A5',
			166 => '=A6',
			167 => '=A7',
			168 => '=A8',
			169 => '=A9',
			170 => '=AA',
			171 => '=AB',
			172 => '=AC',
			173 => '=AD',
			174 => '=AE',
			175 => '=AF',
			176 => '=B0',
			177 => '=B1',
			178 => '=B2',
			179 => '=B3',
			180 => '=B4',
			181 => '=B5',
			182 => '=B6',
			183 => '=B7',
			184 => '=B8',
			185 => '=B9',
			186 => '=BA',
			187 => '=BB',
			188 => '=BC',
			189 => '=BD',
			190 => '=BE',
			191 => '=BF',
			192 => '=C0',
			193 => '=C1',
			194 => '=C2',
			195 => '=C3',
			196 => '=C4',
			197 => '=C5',
			198 => '=C6',
			199 => '=C7',
			200 => '=C8',
			201 => '=C9',
			202 => '=CA',
			203 => '=CB',
			204 => '=CC',
			205 => '=CD',
			206 => '=CE',
			207 => '=CF',
			208 => '=D0',
			209 => '=D1',
			210 => '=D2',
			211 => '=D3',
			212 => '=D4',
			213 => '=D5',
			214 => '=D6',
			215 => '=D7',
			216 => '=D8',
			217 => '=D9',
			218 => '=DA',
			219 => '=DB',
			220 => '=DC',
			221 => '=DD',
			222 => '=DE',
			223 => '=DF',
			224 => '=E0',
			225 => '=E1',
			226 => '=E2',
			227 => '=E3',
			228 => '=E4',
			229 => '=E5',
			230 => '=E6',
			231 => '=E7',
			232 => '=E8',
			233 => '=E9',
			234 => '=EA',
			235 => '=EB',
			236 => '=EC',
			237 => '=ED',
			238 => '=EE',
			239 => '=EF',
			240 => '=F0',
			241 => '=F1',
			242 => '=F2',
			243 => '=F3',
			244 => '=F4',
			245 => '=F5',
			246 => '=F6',
			247 => '=F7',
			248 => '=F8',
			249 => '=F9',
			250 => '=FA',
			251 => '=FB',
			252 => '=FC',
			253 => '=FD',
			254 => '=FE',
			255 => '=FF' 
	);
	protected static $_safeMapShare = array ();
	
	/**
	 * A map of non-encoded ascii characters.
	 * 
	 * @var string[]
	 * @access protected
	 */
	protected $_safeMap = array ();
	
	/**
	 * Creates a new QpEncoder for the given CharacterStream.
	 * 
	 * @param Swift_CharacterStream $charStream
	 *        	to use for reading characters
	 * @param Swift_StreamFilter $filter
	 *        	if input should be canonicalized
	 */
	public function __construct(Swift_CharacterStream $charStream, Swift_StreamFilter $filter = null) {
		$this->_charStream = $charStream;
		if (! isset ( self::$_safeMapShare [$this->getSafeMapShareId ()] )) {
			$this->initSafeMap ();
			self::$_safeMapShare [$this->getSafeMapShareId ()] = $this->_safeMap;
		} else {
			$this->_safeMap = self::$_safeMapShare [$this->getSafeMapShareId ()];
		}
		$this->_filter = $filter;
	}
	public function __sleep() {
		return array (
				'_charStream',
				'_filter' 
		);
	}
	public function __wakeup() {
		if (! isset ( self::$_safeMapShare [$this->getSafeMapShareId ()] )) {
			$this->initSafeMap ();
			self::$_safeMapShare [$this->getSafeMapShareId ()] = $this->_safeMap;
		} else {
			$this->_safeMap = self::$_safeMapShare [$this->getSafeMapShareId ()];
		}
	}
	protected function getSafeMapShareId() {
		return get_class ( $this );
	}
	protected function initSafeMap() {
		foreach ( array_merge ( array (
				0x09,
				0x20 
		), range ( 0x21, 0x3C ), range ( 0x3E, 0x7E ) ) as $byte ) {
			$this->_safeMap [$byte] = chr ( $byte );
		}
	}
	
	/**
	 * Takes an unencoded string and produces a QP encoded string from it.
	 * QP encoded strings have a maximum line length of 76 characters.
	 * If the first line needs to be shorter, indicate the difference with
	 * $firstLineOffset.
	 * 
	 * @param string $string
	 *        	to encode
	 * @param int $firstLineOffset,
	 *        	optional
	 * @param int $maxLineLength,
	 *        	optional, 0 indicates the default of 76 chars
	 * @return string
	 */
	public function encodeString($string, $firstLineOffset = 0, $maxLineLength = 0) {
		if ($maxLineLength > 76 || $maxLineLength <= 0) {
			$maxLineLength = 76;
		}
		
		$thisLineLength = $maxLineLength - $firstLineOffset;
		
		$lines = array ();
		$lNo = 0;
		$lines [$lNo] = '';
		$currentLine = & $lines [$lNo ++];
		$size = $lineLen = 0;
		
		$this->_charStream->flushContents ();
		$this->_charStream->importString ( $string );
		
		// Fetching more than 4 chars at one is slower, as is fetching fewer bytes
		// Conveniently 4 chars is the UTF-8 safe number since UTF-8 has up to 6
		// bytes per char and (6 * 4 * 3 = 72 chars per line) * =NN is 3 bytes
		while ( false !== $bytes = $this->_nextSequence () ) {
			// If we're filtering the input
			if (isset ( $this->_filter )) {
				// If we can't filter because we need more bytes
				while ( $this->_filter->shouldBuffer ( $bytes ) ) {
					// Then collect bytes into the buffer
					if (false === $moreBytes = $this->_nextSequence ( 1 )) {
						break;
					}
					
					foreach ( $moreBytes as $b ) {
						$bytes [] = $b;
					}
				}
				// And filter them
				$bytes = $this->_filter->filter ( $bytes );
			}
			
			$enc = $this->_encodeByteSequence ( $bytes, $size );
			if ($currentLine && $lineLen + $size >= $thisLineLength) {
				$lines [$lNo] = '';
				$currentLine = & $lines [$lNo ++];
				$thisLineLength = $maxLineLength;
				$lineLen = 0;
			}
			$lineLen += $size;
			$currentLine .= $enc;
		}
		
		return $this->_standardize ( implode ( "=\r\n", $lines ) );
	}
	
	/**
	 * Updates the charset used.
	 * 
	 * @param string $charset        	
	 */
	public function charsetChanged($charset) {
		$this->_charStream->setCharacterSet ( $charset );
	}
	
	// -- Protected methods
	
	/**
	 * Encode the given byte array into a verbatim QP form.
	 * 
	 * @param int[] $bytes        	
	 * @return string
	 * @access protected
	 */
	protected function _encodeByteSequence(array $bytes, &$size) {
		$ret = '';
		$size = 0;
		foreach ( $bytes as $b ) {
			if (isset ( $this->_safeMap [$b] )) {
				$ret .= $this->_safeMap [$b];
				++ $size;
			} else {
				$ret .= self::$_qpMap [$b];
				$size += 3;
			}
		}
		
		return $ret;
	}
	
	/**
	 * Get the next sequence of bytes to read from the char stream.
	 * 
	 * @param int $size
	 *        	number of bytes to read
	 * @return int[]
	 * @access protected
	 */
	protected function _nextSequence($size = 4) {
		return $this->_charStream->readBytes ( $size );
	}
	
	/**
	 * Make sure CRLF is correct and HT/SPACE are in valid places.
	 * 
	 * @param string $string        	
	 * @return string
	 * @access protected
	 */
	protected function _standardize($string) {
		$string = str_replace ( array (
				"\t=0D=0A",
				" =0D=0A",
				"=0D=0A" 
		), array (
				"=09\r\n",
				"=20\r\n",
				"\r\n" 
		), $string );
		switch ($end = ord ( substr ( $string, - 1 ) )) {
			case 0x09 :
			case 0x20 :
				$string = substr_replace ( $string, self::$_qpMap [$end], - 1 );
		}
		
		return $string;
	}
}
